Vehicle body front structure

ABSTRACT

A vehicle body front structure includes: a front subframe; left and right suspension lower arms swingably supported by the front subframe; and a steering gearbox supported by the front subframe. The front subframe includes left and right longitudinal members extending in a fore-and-aft direction, a cross member extending laterally and joined to the longitudinal members, and a front lower arm support and a rear lower arm support provided on each longitudinal member to be spaced from each other in the fore-and-aft direction and swingably supporting the corresponding lower arm. The steering gearbox includes a laterally extending rack shaft and a pair of joints provided at either end of the rack shaft and joined to ends of respective tie rods. The longitudinal members extend obliquely so as to approach each other toward rear, and each front lower arm support is positioned more rearward than the steering gearbox.

TECHNICAL FIELD

The present invention relates to a vehicle body front structureincluding a front subframe.

BACKGROUND ART

As a vehicle body front structure of a four-wheel vehicle, there isknown a structure including a pair of left and right front side framesextending in the fore-and-aft direction and a front subframe attached tothe underside of the front side frames (see JP5372130B2, for example).The front subframe supports the arms of the suspensions for suspendingthe front wheels, the steering gearbox, and the driving source, such asan internal combustion engine or an electric motor.

To enlarge the steering range of the front wheels, it is necessary toenlarge the spaces formed on either lateral side of the front subframein which the front wheels are steered. For this purpose, it is necessaryto arrange the suspension arms and the steering gearbox relative to thefront subframe so as not to interfere with the front wheels.

SUMMARY OF THE INVENTION

In view of the above background, a primary object of the presentinvention is to provide a vehicle body front structure including a frontsubframe that can enlarge the steering range of the front wheels.

To achieve the above object, one embodiment of the present inventionprovides a vehicle body front structure (1), comprising: a frontsubframe (6); a pair of left and right lower arms (31) swingablysupported by the front subframe, each lower arm being a part of acorresponding suspension (30); and a steering gearbox (40) supported bythe front subframe, wherein the front subframe includes a pair of leftand right longitudinal members (23) extending in a fore-and-aftdirection, a cross member (24) extending laterally and joined to thelongitudinal members, and a front lower arm support (36) and a rearlower arm support (51) provided on each longitudinal member to be spacedfrom each other in the fore-and-aft direction and swingably supportingthe corresponding lower arm, the steering gearbox includes a laterallyextending rack shaft (42) and a pair of joints (44) provided at eitherend of the rack shaft and joined to ends of respective tie rods (43),the longitudinal members extend obliquely so as to approach each othertoward rear, and the front lower arm supports are positioned morerearward than the steering gearbox.

Thereby, spaces can be formed on laterally outer sides of the steeringgearbox so that the steering range of the front wheels can be enlarged.

Preferably, in plan view, a front end of each front lower arm support ispositioned more forward than a rear end of the cross member, and a rearend of each front lower arm support is positioned more rearward than afront end of the cross member.

Thereby, the front lower arm supports are arranged at positionsoverlapping the cross member in the lateral direction. This allows thelateral force input from each lower arm to the corresponding front lowerarm support to be efficiently transmitted to the cross member so thatthe deformation of the longitudinal members is suppressed.

Preferably, each front lower arm support is joined to the correspondinglongitudinal member and the cross member.

Thereby, the lateral force input from each lower arm to thecorresponding front lower arm support can be efficiently transmitted tothe cross member, and the deformation of the longitudinal members can besuppressed.

Preferably, each lower arm is supported by the corresponding rear lowerarm support at a rear end thereof and includes an arm rear part (31A)extending from the rear end forward and laterally outward in an obliquemanner, an arm curved part (31B) that is laterally curved from a frontend of the arm rear part, and an arm front part (31C) extendinglaterally outward from a laterally outer end of the arm curved part andsupporting a knuckle (32) at a tip end thereof, and each front lower armsupport supports the corresponding lower arm at the arm curved part.

Thereby, large spaces in which the front wheels are steered can beformed in front of the arm front parts of the respective lower arms.

Preferably, the arm front part has a width larger than those of the armrear part and the arm curved part.

Thereby, it is possible to improve the stiffness of a part of each lowerarm where the largest lateral force from the corresponding front wheelis applied.

Preferably, the arm curved part is formed such that a front edge thereofhas a curvature smaller than a curvature of a rear edge thereof.

Thereby, each lower arm can have a width that increases from the armrear part to the arm curved part. Thereby, the stiffness of the armcurved part is improved, and the lower arm can be made resistant todeformation under the lateral force applied from the corresponding frontwheel.

Preferably, the joint is positioned on an extension line obtained byextrapolating the corresponding arm front part in a lengthwise directionwhen the rack shaft is in a neutral position. It is also preferred that,in plan view, a laterally outer edge of each longitudinal member iscurved such that a fore-and-aft central part thereof is recessedlaterally inward.

Thereby, large spaces in which the front wheels are steered can beformed on laterally outer sides of the respective longitudinal members.

Thus, according to one embodiment of the present invention, there isprovided a vehicle body front structure including a front subframe thatcan enlarge the steering range of the front wheels.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bottom view of a vehicle body structure according to anembodiment of the present invention;

FIG. 2 is a bottom view of the vehicle body structure with a frontsubframe and a rear subframe being omitted;

FIG. 3 is a side view of a front part of the vehicle body structure;

FIG. 4 is a bottom view of the front part of the vehicle body structure;

FIG. 5 is a perspective view of the front subframe;

FIG. 6 is a left side view of the front subframe;

FIG. 7 is a sectional view showing a fastening structure between a rearend portion of a front longitudinal member of the front subframe and arear-end support; and

FIG. 8 is a plan view showing the front subframe;

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

In the following, a vehicle body structure according to an embodiment ofthe present invention will be described. In the following description,the fore-and-aft direction, the lateral direction (vehicle widthwisedirection), and the vertical direction are defined with respect to thevehicle. “Laterally inward (vehicle widthwise inner side)” indicates adirection toward the center of the vehicle in the lateral direction, and“laterally outward (vehicle widthwise outer side)” indicates a directionaway from the center of the vehicle in the lateral direction. Theframes, panels, and other members constituting the vehicle bodystructure are made of steel unless otherwise mentioned.

As shown in FIGS. 1 and 2, the vehicle body structure 1 includes a pairof left and right side sills 3 extending in the fore-and-aft directionon either lateral side of a lower part of the vehicle 2, a pair of leftand right front side frames 4 extending in the fore-and-aft direction ina front part of the vehicle 2 and having rear ends connected to thefront ends of the respective side sills 3, and a front subframe 6attached to the underside of the front side frames 4 and supportingfront wheels 5.

A front floor panel 7 is provided on the upper side of the left andright side sills 3 so as to extend between the side sills 3 and has avertically facing surface. As shown in FIG. 3, a pair of left and rightfront pillars 8 are provided at the front ends of the left and rightside sills 3, respectively. Each front pillar 8 extends vertically andhas a lower end joined to the front end of the corresponding side sill3. As shown in FIGS. 1 and 2, a dash panel 9 is provided between theleft and right front pillars 8 so as to have a surface facing in thefore-and-aft direction. The dash panel 9 has left and right side edgesjoined to the left and right front pillars 8, respectively, and has alower edge joined to a front edge of the front floor panel 7.

As shown in FIGS. 1 to 4, the left and right front side frames 4includes front side frame front parts 4A extending in the fore-and-aftdirection at positions laterally inward of and above the left and rightside sills 3, front side frame middle parts 4B extending rearward anddownward from the rear ends of the respective front side frame frontparts 4A, and the front side frame inclined parts 4C (outriggers)extending rearward and laterally outward from the rear ends of therespective front side frame middle parts 4B and connected to the frontends of the corresponding side sills 3.

Each front side frame middle part 4B has a hat-shaped cross-sectionopening upward and is joined to a front face of a lower part of the dashpanel 9 so as to form a closed section structure in cooperation with thedash panel 9. Each front side frame inclined part 4C has a hat-shapedcross-section opening upward and is joined to a lower surface of thefront floor panel 7 so as to form a closed section structure incooperation with the front floor panel 7. Each front side frame inclinedpart 4C has a fore-and-aft width that increases gradually toward thelaterally outward direction and has a laterally outer end joined to alaterally inner surface of the corresponding side sill 3.

As shown in FIG. 3, a bulkhead 11 is provided at the front ends of thefront side frame front parts 4A. The bulkhead 11 includes a pair of leftand right bulkhead side members 11A extending vertically, a bulkheadupper member 11B extending laterally and connecting the upper ends ofthe left and right bulkhead side members 11A, and a bulkhead lowermember 11C extending laterally and connecting the lower ends of the leftand right bulkhead side members 11A, whereby the bulkhead 11 is formedin a rectangular frame shape. The front end of each front side framefront part 4A is joined to a vertically middle part of a rear surface ofthe corresponding bulkhead side member 11A.

A front bumper beam 13 extending laterally is attached to the left andright bulkhead side members 11A via left and right front crash boxes 12serving as shock-absorbing members, respectively. Each front crash box12 is formed in a tubular shape extending in the fore-and-aft direction,having a rear end joined to a vertically middle part of thecorresponding bulkhead side member 11A, and having a front end joined toa rear side of the front bumper beam 13. The front crash boxes 12 havefore-and-aft stiffness lower than that of the front side frames 4, thefront bumper beam 13, and the bulkhead 11, and when a load in a frontalcollision is applied thereto, undergoes deformation earlier than thefront side frames 4, the front bumper beam 13, and the bulkhead 11 toabsorb the impact.

An upper part of each front pillar 8 is provided with a front uppermember 15 which extends forward and then extends forward and downward.Each front upper member 15 is positioned laterally outward and above thecorresponding front side frame front part 4A. The front end of eachfront upper member 15 is joined to the front end portion of thecorresponding front side frame front part 4A via a laterally extendingconnecting member 16. Further, a front damper housing 17 is providedbetween the front side frame front part 4A and the front upper member 15on each lateral side. Each front damper housing 17 includes a verticalwall 17A extending upward from a rear part of the front side frame frontpart 4A and an upper wall 17B extending laterally outward from an upperend of the vertical wall 17A and having a laterally outer end joined tothe front upper member 15.

As shown in FIG. 4, each of the left and right front side frame middleparts 4B is provided with a lateral extension 4D that extends laterally.The laterally inner ends of the left and right lateral extensions 4Dlaterally oppose each other via a gap. The laterally outer end of eachof the left and right lateral extensions 4D is joined to an innersurface of the corresponding front side frame middle part 4B. Eachlateral extension 4D has a hat-shaped cross-section opening upward andforms a closed section structure in cooperation with the front floorpanel 7. Each lateral extension 4D constitutes a part of thecorresponding front side frame 4.

As shown in FIGS. 4 and 7, a guide member 19 is provided on a laterallyinner end of each lateral extension 4D. Each guide member 19 extendsrearward from the lower surface of the laterally inner end of thecorresponding lateral extension 4D. The guide member 19 is provided, ina front lower part thereof, with a slanted surface 19A that is slanteddownward toward the rear. Each lateral extension 4D and thecorresponding guide member 19 constitute a rear-end support 21 thatsupports the rear end of the front subframe 6. Each lateral extension 4Dserves as a fastening seat to which the rear end of the front subframe 6is fastened.

As shown in FIGS. 4 and 5, the front subframe 6 includes a pair of leftand right front longitudinal members 23 extending in the fore-and-aftdirection and a front cross member 24 extending laterally to be joinedto each of the front longitudinal members 23. The left and right frontlongitudinal members 23 extend obliquely laterally inward toward therear such that the distance therebetween decreases toward the rear.Further, the laterally outer edge of each front longitudinal member 23is curved such that the fore-and-aft central part thereof is recessedlaterally inward.

The left and right end portions of the front cross member 24 arerespectively joined to fore-and-aft middle portions of the frontlongitudinal members 23. The left and right end portions of the frontcross member 24 are respectively joined to portions of the frontlongitudinal members 23 slightly forward of the fore-and-aft centersthereof. The front longitudinal members 23 and the front cross member 24each have a closed cross-section. The front edge (front end) of thefront cross member 24 is formed laterally straight. The rear edge of thefront cross member 24 has left and right end portions extending rearwardand laterally outward in an oblique manner. Thereby, the front crossmember 24 has a fore-and-aft width that increases gradually toward thelaterally outward direction.

Behind the front cross member 24, a brace 26 is provided which extendslaterally to connect the left and right front longitudinal members 23.The brace 26 has an X shape in plan view and includes portions extendingfrom the central part thereof in the front left direction, front rightdirection, rear left direction, and rear right direction. The front leftand right end portions of the brace 26 are joined to the left and rightends of the front cross member 24, respectively, and the rear left andright end portions of the brace 26 are joined to the left and rightfront longitudinal members 23, respectively. The brace 26 is preferablyformed of a steel sheet having a vertically facing surface.

As shown in FIG. 4, the front end of each front longitudinal member 23is positioned below the corresponding front side frame front part 4A tobe slightly offset from the same laterally inward. Specifically, alaterally outer part of the front end of the front longitudinal member23 is positioned to overlap a laterally inner part of the front end thefront side frame front part 4A in plan view. Each front longitudinalmember 23 includes, in the front end portion thereof, a front endattachment portion 23A attached to the corresponding front side frame 4.The front end attachment portion 23A is provided in a laterally outerpart of the front end of the front longitudinal member 23. The front endattachment portion 23A of each front longitudinal member 23 and thefront end of the corresponding front side frame front part 4A areconnected to each other by a front connecting member 28 that extendsvertically. Specifically, each front longitudinal member 23 is fastenedto the lower end of the corresponding front connecting member 28 by abolt passed therethrough from below. Each front connecting member 28constitutes a front-end support that supports the front end of the frontsubframe 6. In the present embodiment, the front end attachment portion23A is attached to the front side frame front part 4A indirectly via thefront connecting member 28. In another embodiment, the front endattachment portion 23A may be attached to the front side frame frontpart 4A directly without the front connecting member 28 interposedtherebetween.

The rear end of each front longitudinal member 23 is positioned belowthe corresponding lateral extension 4D. Namely, the rear end of eachfront longitudinal member 23 is positioned more laterally inward thanthe corresponding front side frame middle part 4B. As shown in FIG. 7,the rear end of each front longitudinal member 23 is provided with acollar 29A that vertically extends therethrough. The rear end of thefront longitudinal member 23 is fastened to the lower surface of thelateral extension 4D by a bolt 29B passed through the collar 29A frombelow and threadably engaged with a nut 29C joined to the lateralextension 4D. The rear end of the front longitudinal member 23 protrudesmore rearward than the lateral extension 4D, and the rear edge thereofextends laterally. Further, the rear end of the front longitudinalmember 23 is provided with a vertical width (vertical thickness) thatdecreases gradually toward the rear.

The rear end of the front longitudinal member 23 opposes the slantedsurface 19A of the guide member 19 via a gap in the fore-and-aftdirection. Further, in plan view, the rear end of the front longitudinalmember 23 is positioned to overlap the slanted surface 19A of the guidemember 19.

As shown in FIG. 4, the lower surface of each rear end of the frontlongitudinal member 23 is connected to the lower surface of thecorresponding front side frame middle parts 4B by a plate-shapedconnecting member 27. The connecting member 27 deforms when applied witha load equal to or greater than a predetermined load to release theconnection between the front longitudinal member 23 and the front sideframe middle part 4B.

As shown in FIGS. 1 and 8, a pair of left and right front suspensions 30is provided such that each front suspension 30 is connected to the frontsubframe 6 and the corresponding one of the left and right front sideframes 4. Each front suspension 30 includes a lower arm 31 swingablysupported by the corresponding front longitudinal member 23, a frontknuckle 32 supported by the lower arm 31, and a front shock absorber 33connecting an upper part of the front knuckle 32 and the upper wall 17Bof the corresponding front damper housing 17.

Each lower arm 31 is a so-called A-arm and includes an arm rear part 31Aextending from the rear end forward and laterally outward in an obliquemanner, an arm curved part 31B that is curved laterally outward from thefront end of the arm rear part 31A, and an arm front part 31C extendinglaterally outward from the laterally outer end of the arm curved part31B and supporting the front knuckle 32 at the tip end thereof. The armfront part 31C is formed to have a width larger than those of the armrear part 31A and the arm curved part 31B. On a laterally inner side ofthe arm curved part 31B, a front pivotal support portion 31D is providedto protrude laterally. The front pivotal support portion 31D has an axisthat extends in the fore-and-aft direction. The rear end of the arm rearpart 31A is provided with a rear pivotal support portion 31E having avertically extending axis.

As shown in FIG. 4, each of the left and right front longitudinalmembers 23 is provided with a front lower arm support 36 that supportsthe front pivotal support portion 31D of the lower arm 31 and a rearlower arm support 51 that supports the rear pivotal support portion 31Eof the lower arm 31.

Each front lower arm support 36 is disposed to be generally aligned withthe front cross member 24 laterally, namely, each front lower armsupport 36 is disposed at a position overlapping the front cross member24 in side view and is joined to the corresponding front longitudinalmember 23 and the front cross member 24.

As shown in FIG. 5, each front lower arm support 36 includes a baseportion 36A extending laterally above the corresponding frontlongitudinal member 23 and joined to the front longitudinal member 23and the front cross member 24, and front and rear support walls 36B, 36Ceach joined to the base portion 36A and the front longitudinal member 23and protruding laterally outward from the laterally outer surface of thefront longitudinal member 23.

The base portion 36A is formed in a hollow shape by combining a frontmember and a rear member and is joined to an upper surface and alaterally inner surface of the front longitudinal members 23 and anupper wall of the front cross member 24. The laterally inner end of thebase portion 36A extends through the upper wall of the front crossmember 24 formed in a hollow shape and extends to the interior of thefront cross member 24. The base portion 36A extends from the uppersurface of the front longitudinal member 23 upward and laterally outwardand forms a laterally outer end portion. The laterally outer end portionof the base portion 36A is positioned more laterally outward than thelaterally outer surface of the front longitudinal member 23.

The laterally outer end portion of the base portion 36A is joined to thelower surface of the front side frame front part 4A via a bracket 39.The bracket 39 includes an upper plate portion fastened to the lowersurface of the front side frame front part 4A by a vertically extendingbolt, and a vertical plate portion depending from a laterally inner endof the upper plate portion. The vertical plate portion of the bracket 39contacts a laterally outward-facing end surface of the laterally outerend portion of the base portion 36A and is fastened to the laterallyouter end portion of the base portion 36A by a laterally extending bolt.

An upper part of the base portion 36A forms a slanted portion 36D(connecting portion) that is slanted upwardly from a laterally inner endportion to a laterally outer end portion thereof. Namely, the slantedportion 36D extends in a slanted manner from the front cross member 24to the front side frame front part 4A.

Each of the front and rear support walls 36B, 36C is a plate-like memberhaving a surface facing in the fore-and-aft direction and has alaterally inner edge welded to the laterally outer side of the frontlongitudinal member 23. The rear support wall 36C is positioned behindthe front support wall 36B via a gap. An upper part of the laterallyinner edge of the front support wall 36B extends to above the frontlongitudinal member 23 and is welded to the front face of the baseportion 36A. An upper part of the laterally inner edge of the rearsupport wall 36C extends to above the front longitudinal member 23 andis welded to the rear face of the base portion 36A. A lower part of thelaterally inner edge of each of the front and rear support walls 36B,36C extends to under the front longitudinal member 23 and is welded tothe lower surface of the front longitudinal member 23.

As shown in FIG. 8, the front pivotal support portion 31D of the lowerarm 31 is positioned between the front and rear support walls 36B, 36C.The front pivotal support portion 31D of the lower arm 31 is fitted witha rubber bushing (not shown in the drawings), and a support shaft (notshown in the drawings) is supported on the front and rear support walls36B, 36C so as to extend in the fore-and-aft direction through therubber bushing.

As described above, the front lower arm support 36 includes the baseportion 36A and the front and rear support walls 36B, 36C and swingablysupports the front pivotal support portion 31D of the lower arm 31. Thefront lower arm support 36 is welded to the front longitudinal member 23and the front cross member 24 and is fastened to the front side framefront part 4A via the bracket 39.

As shown in FIG. 4, it is preferred that, in plan view, the frontsupport wall 36B forming the front end of the front lower arm support 36is positioned more forward than the rear end of the lateral end portionof the front cross member 24, and the rear support wall 36C forming therear end of the front lower arm support 36 is positioned more rearwardthan the front end of the front cross member 24. In other words,preferably, the front lower arm support 36 overlaps the front crossmember 24 in side view. In the present embodiment, the front supportwall 36B (the front end of the front lower arm support 36) is positionedmore rearward than the front end of the front cross member 24 and therear support wall 36C (the rear end of the front lower arm support 36)is positioned more forward than the rear end of the front cross member24.

As shown in FIG. 8, a steering gearbox 40 is provided on the uppersurface of the front cross member 24. The steering gearbox 40 includes alaterally extending cylindrical rack housing 41. Inside the rack housing41, a rack shaft 42 is provided to be laterally slidable relative to therack housing 41. The left and right end portions of the rack shaft 42laterally protrude from the rack housing 41 and are connected to theleft and right front knuckles 32 via respective tie rods 43. The rackshaft 42 and each tie rod 43 are connected by a joint 44, which may be aball joint, for example. The left and right joints 44 are arranged inrespective boots 45 which are attached to the left and right ends of therack housing 41, respectively.

At four positions of the front cross member 24; namely, in lateral endportions of the front part of the front cross member 24 and in portionsof the rear part of the front cross member 24 located laterally inwardof the laterally inner end portions of the base portions 36A of the leftand right front lower arm supports 36, collars 47 are provided such thateach collar 47 vertically extends through the front cross member 24 andis welded to the upper wall and the lower wall of the front cross member24. The two collars 47 on the rear side are positioned more laterallyinward than the two collars 47 on the front side.

The lateral end portions of the front part of the rack housing 41 arefastened to the front-side left and right collars 47 provided in thefront cross member 24 by means of bolts. The rear part of the rackhousing 41 is fastened to one of the rear-side left and right collars 47provided in the front cross member 24 by means of a bolt. The shape ofthe rack housing 41 varies depending on the lateral position of thesteering shaft, and one of the rear-side collars 47 to which the rackhousing 41 is fastened is selected in accordance with the shape of therack housing 41. Thus, the rack housing 41 is fastened to the frontcross member 24 at three positions.

The front edge (front end) of each front lower arm support 36 ispositioned more rearward than the front edge (front end) of the frontcross member 24. The laterally inner end portion of the slanted portion36D of each base portion 36A is positioned laterally outward of (to theside of) the upper end of the corresponding rear-side collar 47.

Each rear lower arm support 51 is provided in a part of thecorresponding front longitudinal member 23 between the front lower armsupport 36 and the rear end of the front longitudinal member 23 fastenedto the lateral extension 4D. The rear lower arm support 51 has anopening 51A (see FIGS. 5 and 6) formed in a laterally outer face of thefront longitudinal member 23 and a support shaft (not shown in thedrawings) provided in a deeper side of the opening 51A and extendingvertically to be joined to the upper and lower walls of the frontlongitudinal member 23. The rear pivotal support portion 31E of eachlower arm 31 is fitted with a rubber bushing (not shown in the drawings)through which the support shaft is passed. The rear pivotal supportportion 31E of the lower arm 31 is allowed to move relative to the rearlower arm support 51 by deformation of the rubber bushing. Thereby, eachlower arm 31 is swingably supported to the front subframe 6 by the frontlower arm support 36 and the rear lower arm support 51.

As shown in FIG. 4, in bottom view (or in plan view), the rear lower armsupport 51 on the left side is positioned on an extension line obtainedby extending the left rear end portion of the brace 26. Also, in planview, the rear lower arm support 51 on the right side is positioned onan extension line obtained by extending the right rear end portion ofthe brace 26. The rear lower arm supports 51 are positioned morelaterally inward than the respective front lower arm supports 36.Further, the rear lower arm supports 51 are also positioned morelaterally inward than the left and right joints 44, respectively.

Each front lower arm support 36 is positioned more rearward than thesteering gearbox 40. Each arm front part 31C may extend slightlyobliquely rearward toward the laterally outward direction, and the joint44 on the same lateral side may be provided such that the joint 44 ispositioned on an extension line obtained by extrapolating the arm frontpart 31C in the lengthwise direction when the steering is neutral.

As shown in FIGS. 5 and 6, each front longitudinal member 23 isprovided, in a part thereof forward of the joint with the front crossmember 24, with a deformation promoting portion 53 which has a lowerstiffness than the other part of the front longitudinal member 23. Thedeformation promoting portion 53 is a recess that is formed in the uppersurface of the front longitudinal members 23 to be recessed downward.The deformation promoting portion 53 extends laterally from thelaterally inner surface to the laterally outer face of the frontlongitudinal member 23. When a collision load is applied to the frontlongitudinal member 23 in the fore-and-aft direction, a deformation ofthe front longitudinal member 23 occurs first at the deformationpromoting portion 53, and the front longitudinal member 23 is bentdownward at the deformation promoting portion 53.

A reinforcing plate 54 extends along and is attached to a part of theupper surface of each front longitudinal member 23 located forward ofthe deformation promoting portion 53. A front stabilizer support 56 forrotatably supporting a front stabilizer 55 is provided on eachreinforcing plate 54. The front stabilizer 55 is a rod member includinga laterally extending portion and left and right end portions thatextend rearward from the left and right ends of the laterally extendingportion, respectively. The left and right end portions of the frontstabilizer 55 are joined to the lower ends of the left and right frontshock absorbers 33, respectively, via respective connecting members.Each front stabilizer support 56 is formed with a support hole (notshown in the drawings) through which the laterally extending portion ofthe front stabilizer 55 is passed. A rubber bushing for supporting thelaterally extending portion of the front stabilizer 55 is fitted in thesupport hole of each front stabilizer support 56. Each front stabilizersupport 56 is fastened to the upper surface of the corresponding frontlongitudinal member 23 by means of multiple bolts. A part of each frontlongitudinal member 23 on which the reinforcing plate 54 and the frontstabilizer support 56 are provided is given a higher stiffness than theother part of the same.

In the following, the effects and advantages of the aforementionedembodiment will be described. The rear lower arm supports 51 arepositioned more laterally inward than the respective joints 44 when therack shaft 42 is in the neutral position (or the steering is neutral).Thereby, the rear lower arm supports 51 can be arranged laterally inwardin the vehicle body structure 1. This makes it possible to avoid theinterference between the rear lower arm supports 51 and the front wheels5 so that the steering range of the front wheels 5 can be enlarged.

Also, the front longitudinal members 23 extend obliquely so as toapproach each other toward the rear, and the front lower arm supports 36are positioned more rearward than the steering gearbox 40. Thereby,spaces can be formed on laterally outer sides of the steering gearbox 40so that the steering range of the front wheels 5 can be enlarged.

Because the rear lower arm supports 51 are positioned more laterallyinward than the front lower arm supports 36, the interference betweenthe rear lower arm supports 51 and the front wheels 5 can be avoidedeven further. Since the laterally outer edge of each front longitudinalmember 23 is curved such that the fore-and-aft central part thereof isrecessed laterally inward, the distance between the front longitudinalmember 23 and the corresponding front wheel 5 can be enlarged so thatthe interference between the front longitudinal members 23 and the frontwheels 5 can be avoided even further. These allow the steering range ofthe front wheels 5 to be enlarged.

Because the front lower arm supports 36 are arranged at positionsoverlapping the front cross member 24 in the lateral direction, thelateral force input from each lower arm 31 to the corresponding frontlower arm support 36 can be efficiently transmitted to the front crossmember 24. Thereby, the deformation of the front longitudinal members 23can be suppressed, and driving performance and ride comfort of thevehicle can be improved. Also, because the front lower arm supports 36are joined to the front cross member 24, the lateral force input fromeach lower arm 31 to the corresponding front lower arm support 36 can beefficiently transmitted to the front cross member 24.

The brace 26 improves the stiffness of the front subframe 6, andtherefore, the front subframe 6 is made resistant to deformation underthe lateral force transmitted to the front subframe 6 from either lowerarm 31. Further, because the rear lower arm supports 51 are positionedon the extension lines obtained by extending the respective rear endportions of the brace 26, the lateral force input from either lower arm31 can be efficiently transmitted to the brace 26.

Each lower arm 31 is supported by the corresponding front lower armsupports 36 at the arm curved part 31B thereof, and the front knuckle 32is provided at the tip end of the arm front part 31C extending laterallyoutward from the laterally outer end of the arm curved part 31B.Therefore, large spaces in which the front wheels 5 are steered can beformed in front of the respective arm front parts 31C.

Since the arm front part 31C has a width larger than those of the armrear part 31A and the arm curved part 31B, it is possible to improve thestiffness of a part of each lower arm 31 where the largest lateral forcefrom the corresponding front wheel 5 is applied. Also, since the armcurved part 31B is formed such that a front edge thereof has a curvaturesmaller than a curvature of a rear edge thereof, each lower arm 31 canhave a width that increases from the arm rear part 31A to the arm curvedpart 31B. As a result, the stiffness of the arm curved part 31B isimproved, and the lower arm 31 can be made resistant to deformationunder the lateral force applied from the corresponding front wheel 5.

Concrete embodiments of the present invention have been described in theforegoing, but the present invention should not be limited by theforegoing embodiments and various modifications and alterations arepossible within the scope of the present invention.

The invention claimed is:
 1. A vehicle body front structure, comprising:a front subframe; a pair of left and right lower arms swingablysupported by the front subframe, each lower arm being a part of acorresponding suspension; and a steering gearbox supported by the frontsubframe, wherein the front subframe includes a pair of left and rightlongitudinal members extending in a fore-and-aft direction, a crossmember extending laterally and joined to the longitudinal members, and afront lower arm support and a rear lower arm support provided on eachlongitudinal member to be spaced from each other in the fore-and-aftdirection and swingably supporting the corresponding lower arm, thesteering gearbox includes a laterally extending rack shaft and a pair ofjoints provided at either end of the rack shaft and joined to ends ofrespective tie rods, the longitudinal members extend obliquely so as toapproach each other toward rear, and each front lower arm support ispositioned more rearward than the steering gearbox.
 2. The vehicle bodyfront structure according to claim 1, wherein in plan view, a front endof each front lower arm support is positioned more forward than a rearend of the cross member, and a rear end of each front lower arm supportis positioned more rearward than a front end of the cross member.
 3. Thevehicle body front structure according to claim 2, wherein each frontlower arm support is joined to the corresponding longitudinal member andthe cross member.
 4. The vehicle body front structure according to claim2, wherein each lower arm is supported by the corresponding rear lowerarm support at a rear end thereof and includes an arm rear partextending from the rear end forward and laterally outward in an obliquemanner, an arm curved part that is laterally curved from a front end ofthe arm rear part, and an arm front part extending laterally outwardfrom a laterally outer end of the arm curved part and supporting aknuckle at a tip end thereof, and each front lower arm support supportsthe corresponding lower arm at the arm curved part.
 5. The vehicle bodyfront structure according to claim 4, wherein the arm front part has awidth larger than those of the arm rear part and the arm curved part. 6.The vehicle body front structure according to claim 5, wherein the armcurved part is formed such that a front edge thereof has a curvaturesmaller than a curvature of a rear edge thereof.
 7. The vehicle bodyfront structure according to claim 5, wherein the joint is positioned onan extension line obtained by extrapolating the corresponding arm frontpart in a lengthwise direction when the rack shaft is in a neutralposition.
 8. The vehicle body front structure according to claim 1,wherein in plan view, a laterally outer edge of each longitudinal memberis curved such that a fore-and-aft central part thereof is recessedlaterally inward.